RxKotlin is a lightweight library that adds convenient extension functions to RxJava. You can use RxJava with Kotlin out-of-the-box, but Kotlin has language features (such as extension functions) that can streamline usage of RxJava even more. RxKotlin aims to conservatively collect these conveniences in one centralized library, and standardize conventions for using RxJava with Kotlin.

import io.reactivex.rxkotlin.subscribeBy
import io.reactivex.rxkotlin.toObservable

fun main(args: Array<String>) {

    val list = listOf("Alpha", "Beta", "Gamma", "Delta", "Epsilon")

    list.toObservable() // extension function for Iterables
            .filter { it.length >= 5 }
            .subscribeBy(  // named arguments for lambda Subscribers
                    onNext = { println(it) },
                    onError =  { it.printStackTrace() },
                    onComplete = { println("Done!") }
            )

}

To help cope with the SAM ambiguity issue when using RxJava 2.x with Kotlin, there are a number of helper factories and extension functions to workaround the affected operators.

Observables.zip()
Observables.combineLatest()
Observable#zipWith()
Observable#withLatestFrom()
Flowables.zip()
Flowables.combineLatest()
Flowable#zipWith()
Flowable#withLatestFrom()
Singles.zip()
Single#zipWith()
Maybes.zip()

Use RxKotlin 1.x versions to target RxJava 1.x.

Use RxKotlin 2.x versions to target RxJava 2.x.

RxKotlin can be used in conjunction with other Rx and Kotlin libraries, such as RxAndroid, RxBinding, and TornadoFX/RxKotlinFX. These libraries and RxKotlin are modular, and RxKotlin is merely a set of extension functions to RxJava that can be used with these other libraries. There should be no overlap or dependency issues.

Binaries and dependency information for Maven, Ivy, Gradle and others can be found at http://search.maven.org.

Example for Maven:

<dependency>
    <groupId>io.reactivex</groupId>
    <artifactId>rxkotlin</artifactId>
    <version>1.x.y</version>
</dependency>

and for Gradle:

compile 'io.reactivex:rxkotlin:x.y.z'

Example for Maven:

<dependency>
    <groupId>io.reactivex.rxjava2</groupId>
    <artifactId>rxkotlin</artifactId>
    <version>2.x.y</version>
</dependency>

and for Gradle:

compile 'io.reactivex.rxjava2:rxkotlin:x.y.z'

You can also use Gradle or Maven with JitPack to build directly off a snapshot, branch, or commit of this repository.

For example, to build off the 1.x branch, use this setup for Gradle:

repositories {
    maven { url 'https://jitpack.io' }
}

dependencies {
    compile 'com.github.ReactiveX:RxKotlin:1.x-SNAPSHOT'
}

Use this setup for Maven:

	<repositories>
		<repository>
		    <id>jitpack.io</id>
		    <url>https://jitpack.io</url>
		</repository>
	</repositories>

        <dependency>
	    <groupId>com.github.ReactiveX</groupId>
	    <artifactId>RxKotlin</artifactId>
	    <version>1.x-SNAPSHOT</version>
	</dependency>

Learn more about building this project with JitPack here.

Join us on the #rx channel in Kotlin Slack!

https://kotlinlang.slack.com/messages/rx

We welcome contributions and discussion for new features. It is recommended to file an issue first to prevent unnecessary efforts, but feel free to put in pull requests. The vision is to keep this library lightweight, with a tight and focused scope applicable to all platforms (including Android, server, and desktop). Anything specific to a particular domain (for example, JavaFX, Math, or JDBC) might be better suited as a separate project. Feel free to open discussion and we will help figure out where your functionality may belong.